Secrets
by ArtemisApollo97
Summary: (Better summary inside) Big Three children don't exist. Well, they're not supposed to. Leo was always taught to run if he ever encountered a Big Three child, but no-one believes him when one saves his life from a vicious monster. AU, possible slight OC-ish in some characters as I'm still getting the hang of them :P


**This is an idea from a random dream I had recently. I don't know if it'll go anywhere, but it's set in a similar setting to **_**Apocalyptic Love**_**, but with a different style. Demigods find love in their own time. Not everyone is a demigod, but mortals know about them. The Olympians and minor gods have kids that mingle with mortals except the Big Three. Big Three children are considered rare, dangerous and monstrous, but hopefully I can explain more as/if the story progresses. They're in their late teens in this.**

**I do not own Percy Jackson and co, but Louisa is my OC.**

* * *

"I'm bored."

"Go and make something."

"I've got no ideas!"

"Ugh, just go for a walk then." Nyssa waved him away and Leo had to leave, stumbling out of the forges and strolling off. He saw Frank a short distance down the road, on one of his jogs. Annabeth was in her usual seat at the coffee shop around the corner, with her nose in a book- Leo didn't dare go and disturb her. He kept an eye out for any of his others friends- Piper or Reyna or someone- but they were probably busy keeping demigods in check. Piper used her charmspeak for that and Reyna just had this air of authority about her, being the daughter of Bellona- dangerous girl, that one. She and Annabeth, daughter of Athena, threatened Leo within an inch of his life if he didn't stop annoying them.

Leo glanced up at the sky, seeing a trio of pegasi chasing each other playfully. The sky was a clear crystal blue and a cool summer's breeze danced about, ruffling his curly hair. He pulled some wires from his pockets and started tinkering. He was a son of Hephaestus and tinkering helped keep his mind focused. All demigods were ADHD and they got distracted easily, but depending on their parent, there was always something that could focus them for long enough to think. Annabeth's focus was books, his was tinkering and Reyna's was beating the crap out of people.

He crashed into somebody and looked up, stumbling away.

"Watch where you're going, shrimp."

"Sorry Clarisse." Leo held his work out to her. "Distracted." She just grunted and stomped past him. Leo breathed a sigh of relief. Clarisse, daughter of Ares and half-sister to Frank, even though he was Roman- she had it in for Leo because he was annoying.

He returned to his tinkering, allowing his feet to walk him anywhere. He often did this, losing himself in his work, whatever it was, and he would just walk. It was nice.

* * *

"What are you doin'?" Percy looked up.

"Training. What's it look like?"

"It looks like you need someone to fight."

"Oh, you're ganging up on me too? That's nice." Percy shook his head, smiling at his twin sister and cousin. Louisa was his female clone in everything except personality. They had the same, thick raven hair and the same identical sea green eyes, but she had a shorter temper, a violent streak and attitude worthy of the title sass goddess.

Jason wasn't really like them, except with the immense loyalty they shared with each other. Being cousins, they were the only family they had. Jason was a few months older than the twins with blonde hair and sky blue eyes. He and Percy were lean and muscular, athletic and drawing the attentions of various nymphs.

The three of them and their other cousins- Thalia, Nico and Hazel- lived in a two storey mansion on top of a hill that overlooked the valley. A river circled the eastern side of the hill, twisting and travelling nearly a mile before reaching the sea, the Poseidon twins' home domain.

Jason retrieved his sword and held it out to his cousins challengingly. They simultaneously drew their swords and they stood in a triangle of sorts, looking from one to the other and sizing them up.

They took a step forward when alarms blared and a warning red light filled the room. Louisa grumbled a curse, sheathing her weapon and running out of the room. The boys followed quickly. Louisa was smaller and lighter and outdistanced the pair easily.

Percy and Jason reached the control room shortly after she did. The others were there as well, Nico at the main control panel with Hazel and Thalia either side of him. They all stared up at the big screen, which showed a practically deserted road surrounded by farms. They didn't immediately see what the problem was- they rarely got problems, preferring to keep hidden under their fathers' orders.

A lone guy about their age with elfish features and wild, curly hair strolled along, looking down at something in his hands. It looked like a half-built project and he was intently focused on it.

"Is he a demigod?" Thalia asked. Nico pressed a few buttons and a green bar flickered over the screen, rolling from top to bottom. A panel opened at the side with face recognitions and basic details.

"Leo Valdez, son of Hephaestus, seventeen years old."

"What's he doing so far out of the city?"

"He's a Hephaestus kid. Probably distracted by that project…" Thalia nodded at whatever Leo was holding. "What's the problem then?" Nico pressed another button and the screenshot widened. Leo became a small figure walking along a seemingly never ending road with endless green fields all around him.

Thundering along the road towards him was a powerful she-demon. Kampe.

* * *

Leo was casually minding his own business when he heard the rumbling of thunder. He looked up into the cloudless blue sky and frowned. What was that noise?

He looked forward as an inhuman shriek mingled with the thunderous racket and he saw a large, shadowy figure hurtling towards him in a dust cloud. He looked around and, with a flare of panic, saw he was far out of the city. Demigods who wandered too far out of the city's magical borders were at risk of being tracked by vicious monsters. Most of them had training, but Leo didn't. He had his fire powers, but that was it. No weapons or training or anything.

His project clattered to the floor and he stumbled back. The thing was a hundred paces from him, but he could see the glitter of silvery swords in the midday sun and its wings spread menacingly. It shrieked again, spurring him into a run.

Looking over his shoulder, Leo knew he would never outrun this thing.

"Get down!" He looked round and saw a hooded figure ten feet from him, holding a spear in both hands and pointing it at the monster. Leo dropped to the floor as a metallic taste filled his mouth and his skin tingled.

There was an almighty _crack_ and lightning slammed down from the sky, hitting the spear tip. The figure- a girl- yelled angrily and the lightning shot over his head and skewered the creature straight in the chest.

It gave a dying howl and exploded into yellow dust.

Leo stared at the yellow dust pile, trying to wrap his head around what had just happened. He forced himself to look round at the girl as her hand closed around his arm and he was hauled to his feet. "Get back to the city." She said, giving him a shove. Leo stumbled.

"W-who-? What-?"

"Don't worry about it. Get your project and get moving. You shouldn't be out of the city."

"I know, but I-"

"Rambled." She didn't say anything after that, walking Leo to the city's borders. That took an hour and a bit in itself, but Leo was too stunned to talk, processing what had happened while absent-mindedly fixing his project.

She disappeared the second he was across the barriers. He didn't even get to say thank-you.

"Leo!" Leo turned and saw Frank, Annabeth, Reyna and Piper running towards him. "Where've you been?" Piper demanded, tackling him in a relieved, sisterly hug. "They said you went out of the barriers and-" She spotted the project in his hands and rolled her eyes. "Honestly, Leo, wasn't Nyssa keeping an eye on you?"

"She… let me go out for a walk…" They all frowned.

"Are you OK?" Annabeth asked, feeling his forehead. Leo blinked and his brow furrowed.

"I saw… there was… there was some big thing… and… I panicked… there was this girl and…" Leo stammered out the rest of the story. They didn't seem to believe him though.

"Lightning, Leo?" Reyna challenged when he protested. "That's Big Three stuff. There aren't any known Big Three children alive today."

"How'd you know that?" He countered.

"Have you seen them?"

"I did today."

"Are there any records of half-blood children of the Big Three?"

"I don't know…"

"There aren't. I've checked."

"But what if they're wrong?"

"Leo…"

"She really did use lightning!"

"Leo, you're in shock." Annabeth spoke soothingly, putting her hand on his shoulder. "Let's get you home."

"But-" They insisted on walking him home. They probably thought this was another one of his pranks, but they had to know there was no way he could have defeated a monster on his own. Why didn't they believe him?

* * *

"You were almost found out, Thalia."

"Hey, I was trying."

"Good job Lou used the Mist on those kids." Louisa grinned.

"Nice lightnin', by the way."

"Thanks." Thalia looked back at Nico. "So what if we're found out? It's boring hiding in here all the time- everyone's down there and there's so much more stuff to do and see and-"

"Thalia." Nico spoke calmly, not looking around from the computer screen. He wasn't the oldest, but he was the most mature and the most organised, alongside his sister. There was no real power when he had spoken Thalia's name other than authority, but it was enough to silence the daughter of Zeus. "You know why we can't go down there. We'll attract too much attention and threaten their safety."

"But-" He looked at her and she fell into a sulky silence. Louisa jumped up from her seat on the table- _on the table, in the centre -_ and put her hand on Thalia's shoulder.

"Ya owe me a sparrin' match, remember?"

"Fine…" Thalia followed Louisa out. "I understand about the whole safety thing, but it sucks living up here with barely anyone to talk to. There's no change, it's just training and training all the time and we only show up when we have to for the rare problem. I'm _bored_."

"Yeah, me too." Louisa pulled a face. "Unless ya wanna sneak out." Thalia looked at her. Louisa had sneaked out before. Only Thalia and Percy knew- Percy had nearly set fire to the kitchen to cause a big enough distraction for Louisa to slip out and Thalia had seen her climb through a window to get back in. That was the only time Thalia knew of Louisa sneaking out- Poseidon's daughter had probably done that hundreds of times without Nico finding out.

"Fine. When?"

"Tonight. Be a piece of cake." She reached into her pocket and retrieved what looked like an MP3 player. "This thing jams Nico's computer thing 'n' I can get out without the CCTV catchin' me."

"You're good."

"Yes, I know."

* * *

Leo sat up later that night, going over what he had seen today.

That was definitely a Big Three child. No-one else could use lightning and fry a monster like that. It annoyed him that his friends didn't believe him; annoyed him to the point of flames curling from his fingers. He didn't lie about stuff like this and- what was that noise?

Leo looked at the window. It sounded like a cat screeching, but there was something different…

He got up and pulled the Batman curtains back, looking around and trying to spot something in the light of the stars and moon. He didn't see a cat, but two shadowy figures hitting each other, apparently arguing. Leo opened the window and leaned out. The cool night air sent chills down his spine, but he had his own central heating system and rarely got cold.

"Stop it." Somebody hissed.

"You've got us lost."

"I haven't! I took a shortcut 'n'-"

"We're lost, aren't we?"

"No."

"Didn't you hear that alarm?"

"Oh, pfft. Alarms are for babies."

"Lou…"

"What?"

"Nico's going to kill us if we get found out."

"You're a daughter of Zeus for cryin' out loud! Why're ya scared of him?"

"He raises armies of the dead and can kill us with a thought. I'm not scared, just worried."

_Daughter of Zeus?_ Leo thought, straining his ears to listen for more. Was that the girl from earlier who had zapped the monster and saved his life?

"They're here somewhere!" Leo looked to the left and his heart started hammering in his chest. "Find them before they bring Growlies with them!"

"Yes sir!" A chorus of voices replied. The squadron split up, six of them filing down this street.

"I told you there'd be trouble!"

"That was your fault." The other one sounded calm, peering around the corner at the legionaries. The legionaries were mainly made up of children of Ares and/or Mars and were tough, disciplined and often harsh, yet they protected the city and sought out rogue demigods.

"What do we do?"

"Piece of cake." Something glinted in their hand and Leo drew a sharp breath at the sight of the sword. She stepped out in full sight of the legionaries, giving a sharp whistle. They instantly stood shoulder-to-shoulder, forming a shield wall. Leo scrambled for his phone and started recording the fight that was sure to happen.

"Who are you?" One of the legionaries called.

"Just a visitor."

"Demigod or mortal?"

"Demigod."

"Sir, the readings are off the chart!"

"Big Three…"

"Guilty." The girl with the sword sounded quite pleased with herself.

"You are not allowed in the city."

"That's not fair."

"By orders of the praetors, any Big Three child is to be bought to them for threatening the safety of the city. Come quietly and the consequences will be more lenient."

"I don't do quiet." She held up her sword, green energy sparking along her arm. The legionaries tightened the shield war, weapons bristling over the top. The other Big Three child stepped out, tapping something shiny on her wrist and gaining a shield. Leo winced at the sight of Medusa on the surface of the shield, but recognised the girl's spear. He wasn't crazy! They existed!

The legionaries didn't look comfortable. No-one knew the true extent of Big Three powers, but they all knew the tales.

_If you meet a Big Three child, it will be a miracle to walk away alive._

_They eat the hearts of their victims and take their heads, shrinking them and keeping them as souvenirs._

_They show no mercy, leaving destruction wherever they roam._

_Some are said to have amazing mind powers and skin you alive with a single thought or turn you inside out. _

Leo shoved aside the tales he had been told as a child- their teacher's job was to warn them of Big Three children, telling them to run if they were ever in the presence of one. Leo had asked how to tell if they were a Big Three child, but the answer had been _power_.

_You will feel the power rolling off of them like light from the sun. They are powerful, uncontrollable beings with no means of restrictions. _

The green light slashed through the air, scattering the legionaries. Should there have been more of them; it would have been easier to spur a counter attack. But there were only six and they were easily out powered against two Big Three children.

Suddenly, everything started shaking violently. Leo fell to his knees, gripping the window ledge for support. Yells outside were mostly drowned out by a long, jagged cracking sound. Leo looked out of the window and stared in horror.

"Look what've they done!" One of the legionaries cried, pointing at the sky.

The barriers… they were visible, like pale blue glass, but with large cracks that spread.

"That's not us." The one with the spear looked at her friend. "Lou, what's happening?"

"I don't know. But that's not us."

"It has to be!" The one with the sword- Lou- waved her hand and the one who had argued back shot back on a strong sea wind, slamming into a wall and crumpling to the floor in an unconscious heap.

"We have to go."

"Aw, buzzkill, Thals. We just got here."

"I know, but all these people… the barriers… if that's not us, what's breaking them?"

"Somethin' bad, probably."

"Lou, come on!"

More legionaries had appeared, blocking either end of the street and covering the alley opposite Leo's window. He held his phone steady, set to get this all on video.

"What are you doing to the barriers?"

"That's not us." The one with the spear protested, her voice rippling with anger and carrying across the formations. "I swear it on the River Styx." There was a shocked intake of breath and everything stilled suddenly, an eerie quiet. Thunder boomed in the distance, mingling with the cracks of the barrier.

"She… she's telling the truth…"

"Sir, what do we do?"

"Our job. They are to be taken to the praetors and dealt with there." The legionaries swarmed forward, but Lou stepped forward and held her hands out.

"Stop." Her voice was powerful, flowing easily. Leo froze himself, the legionaries halting and looking confused. "That," She pointed at the sky, indicating the barriers, "is more important than us. Ya wanna get that up 'n' runnin' before tryin' ta catch us."

"You're breaking laws."

"Yeah, I know. But damn, it's fun."

* * *

Leo ran into the room, startling Frank and making the son of Mars spill coffee on himself.

"I've got proof!" He beamed, waving his phone in the air.

"Of what?" Leo collapsed in a seat next to Annabeth and showed them the video he had recorded last night.

They were in a stunned silence for a few minutes, before they all started stammering apologies. Leo waved it off, grinning.

"I sent it in to a news station. Look!" He pointed at the TV.

"Myths of Big Three children circulate and rumours are spread, but it was never proven that they existed until shocking footage from an anonymous source was sent to us in the early hours of this morning." Clips of Leo's video appeared, showing 'Lou' waving her hand and sending that guy flying, the burst of green energy and the number of legionaries. It also showed the barriers breaking. "Fears and tensions are running high as the barriers protecting our city weaken. One of the Big Three children swore on the River Styx that they were not the cause of this fault and Hecate's children are said to be investigating, alongside our beloved praetors."

* * *

"Louisa and Thalia to the main room _now_!"

"Uh oh, he sounds mad."

"Yeah…"

"What did you do?" Percy asked, leaning forward in his seat. Thalia glared at Louisa, who smiled sweetly.

"Why don't ya tag along 'n' find out?" Percy, Jason and Hazel shared glances before getting up and following their cousins out.

Nico was fuming when they entered the control room. The news was on.

"What is this?" He demanded, jabbing a finger furiously at the screen.

"Um… a walk."

"We're supposed to stay _here_!"

"We know, but we got bored."

"Those people, Louisa! Thalia, you should know better! Those people were put at risk _and_ you were caught on _camera_."

"Well, if we saw the guy with the camera, we'd have kicked his face in. But there were legionaries tryin' ta get us, so…"

"Oh, yeah, the _legionaries_ _saw you_. We're not supposed to _exist_."

"Well, we do and it's kinda pointless hiding out here when we can be down there and helping to keep the city safe." Nico sighed, pinching the bridge of his nose tiresomely.

"Nico, you need to sleep." Percy stepped forward. "Me and Jason will keep an eye on things. You go and get some kip, OK?"

* * *

**Alright, that's all I've got. Maybe or maybe not I can carry on with this. What do you guys think? **


End file.
